Present-day foil bearing and magnetic bearing technologies are fully matured and separately have been utilized in a wide variety of high speed turbomachinery. Both types of bearings have significant advantages compared to conventional bearings (ball bearing and hydrostatic bearing). One major advantage is that they do not require an external lubrication system, which leads to a more robust and reliable system.
Magnetic bearings, however, require back up bearings to support the rotor and to prevent damage in the event of electrical power disruption or when the unit is in transit.
Foil bearings are an excellent choice as backup bearings for applications where very low bearing start torque and power loss are required.